Maternal Ethanol Research Articles

Maternal Ethanol Exposure Is Associated With Decreased Plasma Zinc and Increased Fetal Abnormalities in Normal but Not Metallothionein-Null Mice

Maternal Ethanol Exposure Is Associated With Decreased Plasma Zinc and Increased Fetal Abnormalities in Normal but Not Metallothionein-Null Mice

Maternal Ethanol Exposure Is Associated With Decreased Plasma Zinc and Increased Fetal Abnormalities in Normal but Not Metallothionein‐Null Mice

Ethanol profoundly affects fetal development, and this is proposed to be due primarily to a transient fetal zinc (Zn) deficiency that arises from the binding of Zn by metallothionein (MT) in the maternal liver. Zn homeostasis and fetal outcome were investigated in normal (MT+/+) and metallothionein-null (MT-/-) mice in response to ethanol exposure. Mice were treated with saline or ethanol (0.015 m/g intraperitoneally at 0 and 4 hr) on day 8 of gestation (Gd8), and the degree of fetal dysmorphology was assessed on Gd18. The incidence of external abnormalities was significantly increased in offspring from MT+/+ dams exposed to ethanol, where 27.4% of fetuses were affected. MT-/- ethanol-, MT+/+ saline-, and MT-/- saline-treated dams had fetuses in which the frequencies of abnormalities were 2.2, 6.4, and 6.9%, respectively. To investigate Zn homeostasis, nonpregnant mice were killed at intervals over 16 hr after ethanol injection. Liver MT concentrations in MT+/+ mice were increased 20-fold by 16 hr, with a significant elevation evident by 4 hr, whereas liver Zn levels were also significantly increased by 2 hr and maintained for 16 hr. In parallel with these changes, plasma Zn concentrations in MT+/+ mice decreased by 65%, with minimum levels of 4.5+/-0.3 micromol/liter at 8 hr. Conversely, MT-/- mice exhibited increased plasma Zn concentrations, with peak values of 20.8+/-0.3 observed at 4 hr. These findings link the teratogenic effect of ethanol to the induction of maternal MT and the limitation of fetal Zn supply from the plasma.

Genetic and Developmental Modulation of Cardiac Deficits in Prenatal Alcohol Exposure

Increasing evidence demonstrates that genetic background is an important modulator of alcohol's effects on the developing fetus. Such effects are separable from maternal ethanol metabolism. Here, we study ethanol's effects on cardiogenesis in an avian model that shows strong cell death within neuronal and neural crest precursors following ethanol exposure. The study design tested the hypothesis that ethanol-induced losses of cardiac neural crest populations would disrupt outflow tract development and thus contribute to the valvuloseptal deficits observed in prenatal alcohol exposure. Three chick strains were exposed to alcohol at gestational windows between gastrulation and early heart septation (day 3 incubation), and then hearts were examined at the completion of morphogenesis (day 10 incubation). Ethanol's impact on cardiac development was influenced by fetal genetics. The B300 x Hampshire Red cross exhibited pronounced cell death within cardiac neural crest populations but had normal development of the heart and aortic arches. Neural crest migration and differentiation into the distal outflow tract were also normal in these embryos, which suggested a capacity to repair earlier losses. The DeKalb White x Hampshire Red cross also did not exhibit cardiac defects. Hearts of the B300 strain had a unique phenotype with respect to ethanol exposure and exhibited a thin ventricular compact layer, dilatation, and reduced myosin/deoxyribonucleic acid and myosin/protein content, a phenotype that indicates disrupted myocardial maturation and inductive cues. The deficit was only observed when ethanol exposure occurred at stages 15 or 18 and apparently was independent of neural crest cell death. Such ventricular thinning might go undetected in the absence of extensive screening. Results add to the increasing evidence that genetic background strongly modulates the effects of prenatal alcohol exposure. The results also suggest that embryos have a varying capacity to repair and recover from earlier neural crest losses.

Developmental aspects of intestinal intraepithelial and lamina propria lymphocytes in the rat following placental and lactational exposure to ethanol.

Fetal and lactational exposure to alcohol can induce impairments to the immune system and lead to decreased resistance to certain infectious agents. Morphometric procedures were used to quantify changes induced by maternal ethanol consumption in the gut-associated lymphoid tissue of rat pups. Rats were pair-fed with ethanol-containing or isocaloric control liquid diets formulated for pregnant and lactating animals from day 1 of pregnancy and throughout the lactation periods. Pups were weaned and placed on control liquid diet on post-natal day 21. Intraepithelial and lamina propria lymphocytes and macrophages were evaluated on post-natal days 14, 18, and 25. Lower thymus weights were observed in the ethanol-exposed pups on post-natal days 14 and 18 and lower total thymocyte counts on post-natal day 14. On post-natal day 14, T cells, T cytotoxic cells, IgA plasma cells, and macrophages were decreased in the ileal epithelial and lamina propria areas in the ethanol-exposed, compared to the pair-fed, pups. No differences for any of the above cell counts were found in the jejunum on post-natal day 14. On post-natal day 18, macrophages were still decreased in the ileum in the ethanol-treated pups, compared to pair-fed animals. No differences were found in T cells, T cytotoxic cells, and IgA lymphocytes between groups in either the jejunum or ileum on post-natal days 18 and 25. This study suggests that fetal and lactational exposure to ethanol has some effects on the development or influx of intraepithelial and lamina propria leukocytes and that the changes are most pronounced in early neonatal life.

Genetic and Developmental Modulation of Cardiac Deficits in Prenatal Alcohol Exposure

Background: Increasing evidence demonstrates that genetic background is an important modulator of alcohol's effects on the developing fetus. Such effects are separable from maternal ethanol metabolism. Here, we study ethanol's effects on cardiogenesis in an avian model that shows strong cell death within neuronal and neural crest precursors following ethanol exposure. Methods: The study design tested the hypothesis that ethanol-induced losses of cardiac neural crest populations would disrupt outflow tract development and thus contribute to the valvuloseptal deficits observed in prenatal alcohol exposure. Three chick strains were exposed to alcohol at gestational windows between gastrulation and early heart septation (day 3 incubation), and then hearts were examined at the completion of morphogenesis (day 10 incubation). Results: Ethanol's impact on cardiac development was influenced by fetal genetics. The B300 X Hampshire Red cross exhibited pronounced cell death within cardiac neural crest populations but had normal development of the heart and aortic arches. Neural crest migration and differentiation into the distal outflow tract were also normal in these embryos, which suggested a capacity to repair earlier losses. The DeKalb White X Hampshire Red cross also did not exhibit cardiac defects. Hearts of the B300 strain had a unique phenotype with respect to ethanol exposure and exhibited a thin ventricular compact layer, dilatation, and reduced myosin/deoxyribonucleic acid and myosin/protein content, a phenotype that indicates disrupted myocardial maturation and inductive cues. The deficit was only observed when ethanol exposure occurred at stages 15 or 18 and apparently was independent of neural crest cell death. Such ventricular thinning might go undetected in the absence of extensive screening. Conclusions: Results add to the increasing evidence that genetic background strongly modulates the effects of prenatal alcohol exposure. The results also suggest that embryos have a varying capacity to repair and recover from earlier neural crest losses.

Influence of Fetal Alcohol Exposure on the GABAergic Regulation of Growth Hormone Release in Postnatal Rats

Disruption of the growth hormone (GH) axis by maternal ethanol (ETOH) consumption may contribute to abnormalities in offspring. Interestingly, gamma-aminobutyric acid (GABA) neurotransmission, which is vulnerable to fetal ETOH exposure, also regulates the hypothalamic-pituitary GH axis. This study examines whether GABAergic control of this axis is disrupted by prenatal ETOH exposure. Pregnant dams were fed either rat chow ad libitum or a 36% ETOH diet (by calories), or were pair-fed an isocaloric control diet. Hypothalami and pituitaries from offspring were coperfused, in vitro, with muscimol, a GABA(A) agonist, either alone or in combination with bicuculline, a GABA(A) antagonist. Perfusates were analyzed by radioimmunoassay for GH, somatostatin (SRIF), and GH-releasing factor (GRF). Normal development of GABA regulation was evaluated first in control offspring. Sensitivity to muscimol (measured by percent increase in GH above basal levels) occurred at all ages and generally was greater in male compared to female tissue. Furthermore, the efficacy of bicuculline in depressing muscimol-induced GH secretion increased with age in both sexes. In males, this response correlated with increased SRIF release. In females, releasing factor data were highly variable relative to the percent change and are not presented. Maternal ETOH consumption altered the development of GABAergic regulation of the GH axis in offspring. flowever, because ETOH induced changes in the response of releasing factors to muscimol appear to offset each other, a disruption in GH release was not evident. More apparent was the reduced capacity of bicuculline to reverse muscimol-induced GH release from male tissue. This ETOH effect was evident at 35-days of age and was associated with reduced SRIF release. In female tissue, a reduced bicuculline response was also suggested at 35 days of age. After puberty no response was elicited by muscimol in either tissue from pair-fed or ETOH-exposed female offspring. In summary, fetal ETOH exposure influences the development of GABAergic regulation of the hypothalamic-pituitary GH axis in an age and gender specific manner. Vulnerability of the male axis is expressed by the reduced capacity of bicuculline to depress GH release and altered releasing factor sensitivity to GABA(A)-receptor stimulation or inhibition. There is also some suggestion that the female axis is less sensitive to bicuculline during early puberty, and, unlike the male, is insensitive to both muscimol and bicuculline after puberty. The latter, however, may be attributable to stress or nutritional deprivation, rather than to the direct effect of prenatal ETOH.

Reduced Gene Expression for Dopamine Biosynthesis and Transport in Midbrain Neurons of Adult Male Rats Exposed Prenatally to Ethanol

Prenatal ethanol exposure affects brain dopaminergic neuronal systems, and many of these alterations are permanent. The primary objective of this study was to determine the effects of prenatal ethanol exposure on adult mRNA expression for two key regulatory proteins in the mesolimbic and nigrostriatal dopaminergic cell groups which mediate behavioral responses to alcohol and other drugs of abuse: tyrosine hydroxylase (TH) and dopamine transporter (DAT) in the substantia nigra pars compacta (SNpc) and ventral tegmental area (VTA). To also address the effects on noradrenergic regulation, we quantitated mRNA expression for TH and norepinephrine transporter (NET) in the noradrenergic loci of the locus coeruleus (LC). Daily dietary ethanol consumption by female Sprague-Dawley rats for 3 weeks before, and continuing throughout, pregnancy decreased both DAT (approximately 68%,p < 0.002) and TH (approximately 45%,p < 0.002) mRNA expression in the VTA of adult male offspring. This prenatal exposure also suppressed DAT mRNA expression in the SNpc (approximately 81 %;p < 0.03), although TH mRNA expression in this region was not significantly altered. Prenatal ethanol exposure did not alter significantly either TH or NET mRNA expression in the LC of adult male offspring, which suggests that this brain catecholaminergic response may be limited to DA neurons. These results demonstrated that prenatal maternal ethanol consumption suppresses mRNA expression for important regulatory proteins in the mesolimbic and nigrostriatal dopaminergic systems of adult male rat offspring. These persistent prenatal ethanol-induced changes in mRNA expression may thus contribute to the persistent effects of fetal ethanol exposure on the diverse behavioral and/or metabolic responses mediated by the mesolimbic and nigrostriatal dopaminergic systems in the adult.

Reduced Gene Expression for Dopamine Biosynthesis and Transport in Midbrain Neurons of Adult Male Rats Exposed Prenatally to Ethanol

Background: Prenatal ethanol exposure affects brain dopaminergic neuronal systems, and many of these alterations are permanent. Methods: The primary objective of this study was to determine the effects of prenatal ethanol exposure on adult mRNA expression for two key regulatory proteins in the mesolimbic and nigrostriatal dopaminergic cell groups which mediate behavioral responses to alcohol and other drugs of abuse: tyrosine hydroxylase (TH) and dopamine transporter (DAT) in the substantia nigra pars compacta (SNpc) and ventral tegmental area (VTA). To also address the effects on noradrenergic regulation, we quantitated mRNA expression for TH and norepinephrine transporter (NET) in the noradrenergic loci of the locus cocruleus (LC). Results: Daily dietary ethanol consumption by female Sprague-Dawley rats for 3 weeks before, and continuing throughout, pregnancy decreased both DAT (∼ 68%, p < 0.002) and TH (∼ 45%, p < 0.002) mRNA expression in the VTA of adult male offspring. This prenatal exposure also suppressed DAT mRNA expression in the SNpc (∼ 81%; p < 0.03), although TH mRNA expression in this region was not significantly altered. Prenatal ethanol exposure did not alter significantly either TH or NET mRNA expression in the LC of adult male offspring, which suggests that this brain catecholaminergic response may be limited to DA neurons. Conclusion: These results demonstrated that prenatal maternal ethanol consumption suppresses mRNA expression for important regulatory proteins in the mesolimbic and nigrostriatal dopaminergic systems of adult male rat offspring. These persistent prenatal ethanol-induced changes in mRNA expression may thus contribute to the persistent effects of fetal ethanol exposure on the diverse behavioral and/or metabolic responses meditated by the mesolimbic and nigrostriatal dopaminergic systems in the adult.

Prenatal ethanol effects on NGF level, NPY and ChAT immunoreactivity in mouse entorhinal cortex: a preliminary study.

It has been reported that maternal ethanol consumption leads to deficits in the limbic areas involved in cognitive functions and interferes with synthesis and utilization of neurotrophins. In the present study, it was hypothesized that prenatal alcohol intake might induce neuroanatomical alterations in the entorhinal cortex (EC). We also investigated the possible EC involvement of brain nerve growth factor (NGF), the first neurotrophin to be isolated, during such pathological events. To test this hypothesis, we used pregnant mice exposed to ethanol during EC neurogenesis (starting about gestational day 8). Our data show that prenatal alcohol intake in male mice alters the EC neuronal growth and differentiation. These morphological alterations are accompanied by an altered NGF level in the EC of prenatal alcohol-treated mice. We also found a decrease in choline acetyltransferase- and neuropeptide Y-immunopositive neurons in the EC of alcohol-exposed mice. However, the relationship between neuronal damage induced in the EC by ethanol, low presence of NGF, and the possible functional and behavioral consequences remains to be elucidated.

Folic acid intestinal absorption in newborn rats at 21 day postpartum: Effects of maternal ethanol consumption

This study was designed to examine the effects of prenatal and postnatal exposure of ethanol in the in vivo absorption of free folic acid in the small intestine in pups rats at the 21 st day after birth. The rats were accustomed to increasing amounts of ethanol (5 to 20%, vol/vol) in tap water for 1 month. During pregnancy and suckling period, ethanol-fed dams were assigned again to ethanol 20% in drinking water. Two sets of experiments were performed. In the first set, jejunal free folic acid absorption in control group and litters nursed by dams receiving ethanol showed a gradual increase along with the increase of perfusion time at all the assayed concentrations. In general, in litters of ethanol-fed dams, jejunal free folic acid absorption expressed as nmol/intestinal surface, nmol/g tissue wet weight and nmol/g tissue dry weight were higher than in control animals. In the second set of experiments, in distal ileum loops, free folic acid absorption did not occur in control pups, but appeared in litters exposed to ethanol. Milk folic acid levels are significantly decreased in ethanol-treated dams. However, only a slight decrease in the serum folic acid levels occurs in litters of ethanol-fed dams. In conclusion, the results obtained in the present work suggested a different pattern of free folic acid absorption in distal ileum for the two groups. The exposure of rats to ethanol during the pregnancy and suckling period, can affect postnatal development of intestinal functions and could play a role in the genesis of malnutrition observed in the infant.

Increased cerebral extracellular adenosine and decreased PGE2 during ethanol-induced inhibition of FBM.

Adenosine and PGE2 are neuromodulators, both of which inhibit fetal breathing movements (FBM). Although circulating PGE2 has been implicated as a mediator of ethanol-induced inhibition of FBM in the late-gestation ovine fetus, a role for adenosine has not been examined. The objective of this study was to determine the effect of maternal ethanol infusion on ovine fetal cerebral extracellular fluid adenosine and PGE2 concentrations by using in utero microdialysis and to relate any changes to ethanol-induced inhibition of FBM. Dialysate samples were obtained from the fetal parietal cortex over 70 h after surgery to determine steady-state extracellular fluid adenosine and PGE2 concentrations. On each of postoperative days 3 and 4, after a 2-h baseline period, ewes received a 1-h infusion of ethanol (1 g/kg maternal body wt) or an equivalent volume of saline, and the fetus was monitored for a further 11 h with 30-min dialysate samples collected throughout. Immediately after surgery, dialysate PGE2 and adenosine concentrations were 3.7 +/- 0.7 and 296 +/- 127 nM, respectively. PGE2 did not change over the 70 h, whereas adenosine decreased to 59 +/- 14 nM (P < 0.05) at 4 h and then remained unchanged. Ethanol decreased dialysate PGE2 concentration for 2 h (3.3 +/- 0.3 to 1.9 +/- 0.4 nM; P < 0.05) and increased adenosine concentration for 6 h (87 +/- 13 to a maximum of 252 +/- 59 nM, P < 0.05). Ethanol decreased FBM incidence from 47 +/- 7 to 16 +/- 5% (P < 0.01) for 8 h. Saline infusion did not change dialysate adenosine or PGE2 concentrations or FBM incidence. These data are consistent with the hypothesis that fetal cerebral adenosine, and not PGE2, is the primary mediator of ethanol-induced inhibition of FBM at 123 days of gestation in sheep.

Ethyl Linoleate in Meconium: A Biomarker for Prenatal Ethanol Exposure

Fetal alcohol syndrome, fetal alcohol effects, alcohol-related neurodevelopmental disorder, and alcohol-related birth defects, all terms referring to the spectrum of consequences of in utero exposure to ethanol, are a major public health burden. There is currently no laboratory test to identify newborns exposed to ethanol in utero. Meconium was analyzed for ethyl linoleate, a metabolite of ethanol, as a biological marker for fetal ethanol exposure. Samples of meconium were obtained from 248 infants and analyzed for fatty acid ethyl esters. Detailed maternal alcohol, tobacco, and drug use histories were obtained within 1 month of giving birth. The detection of ethyl linoleate in meconium was called a positive test. The mean number of drinks reported per week in the month before pregnancy, the first trimester, and overall were significantly higher in the positive group (unadjusted: 9.2 +/- 1.9 vs. 4.3 +/- 1.4, p = 0.004; 7.3 +/- 1.7 vs. 3.8 +/- 1.2, p = 0.03; and 6.1 +/- 1.3 vs. 3.0 +/- 1.0, p = 0.006). A positive test was not associated with marijuana, cocaine, or tobacco use. Sensitivity and specificity of the test were 72% and 51% to distinguish women who reported 1 or more drinks/week in the third trimester from women who denied use, and 68% and 48% to distinguish women who used > or =1 drink/week from women who used <1 drink/week in the month before pregnancy. The presence of ethyl linoleate in meconium is the first reported biological marker for maternal ethanol use during pregnancy. Because of the inherent inaccuracy associated with the use of self-reporting, the establishment of true values of sensitivity and specificity will require validation where the presence, quantity, and timing of exposure to alcohol is known. Further validation of this marker will permit identification and intervention of at-risk infants.

The Antioxidants Vitamin E and β-Carotene Protect Against Ethanol-Induced Neurotoxicity in Embryonic Rat Hippocampal Cultures

Fetal alcohol syndrome is characterized by numerous nervous system anomalies with the developing hippocampus being highly vulnerable. Other conditions can result from maternal ethanol consumption including oxidative stress. Critical antioxidants, such as vitamin E, can be decreased and antioxidative defenses altered. Gestational day 18 rat hippocampal cultures were exposed to ethanol ranging from 400 to 2400 mg/dl (16 h). MTT assays assessed neurotoxicity. Viability was decreased dose dependently. Supplementation with vitamin E or β-carotene afforded neuroprotection against all ethanol concentrations. Vitamin E completely ameliorated neuronal loss following 400 and 800 mg/dl ethanol. Vitamin E increased survival to 95%, 79%, 66%, and 75% during 1600, 1800, and 2000 and 2400 mg/dl ethanol compared to nonethanol treatment. Vitamin E increased viability by 38%, 23%, 12%, and 29% at 1600, 1800, 2000, and 2400 mg/dl compared to non-vitamin E-supplemented, ethanol treatment. β-Carotene completely ameliorated cell loss from 400 mg/dl ethanol and increased survival by 18% at 1600 mg/dl and 12% at 2000 mg/dl. This study demonstrates in vitro antioxidative neuroprotection against developmental ethanol exposure and suggests that nutritional therapies incorporating antioxidants may help protect against deleterious fetal effects from maternal alcohol abuse.

Ethanol, oxidative stress, reactive aldehydes, and the fetus.

The fetotoxic effects of maternal ethanol (E) consumption have been documented for over two decades, yet the mechanisms underlying this devastating phenomenon remain uncertain. The wide variety of cellular/biochemical effects of E on fetal tissues is itself a puzzle and strongly suggests that fetotoxic responses to E reflect a multifactorial setting. Many of these responses can be conceptually connected to effects on membrane structure and function. Representative of this, are studies in our laboratory documenting E effects on fetal cell replication, membrane transport systems, membrane fluidity, Na+-K+ pump expression, and EGF receptor expression. Recent studies have provided evidence that oxidative stress may be one mechanism by which E produces these membrane-related events. We initially observed E-induced oxidative stress in cultured fetal rat hepatocytes, the latter exhibiting morphological and biochemical signs of mitochondrial damage. E increased H2O2, O2-, lipid peroxidation products, along with signs of membrane damage. Supplementation with antioxidants or agents that enhance glutathione stores reversed these effects. E was found to inhibit activities of mitochondrial respiratory chain components (a potential source of the enhanced levels of H2O2, and O2-) and this could be reversed by antioxidant treatment. Subsequent studies have documented oxidative stress and membrane lipid peroxidation in fetal brain and liver (gestation day 19) following a two day maternal E consumption and in gestation day 14 and 17 "embryos" immediately following a single dose of E to the pregnant dam. The means by which E can induce oxidative stress in fetal cells is under investigation. We have examined effects of E on activities of key antioxidant enzymes and found no depressant responses. However, the low levels of antioxidants in fetal tissues and an exaggerated response of fetal mitochondria to prooxidant stimulation in vitro, suggest that fetal cells are strongly predisposed to oxidative stress. Additionally, recent studies have suggested that fetal tissues are likewise prone to the formation and subsequent accumulation of at least one toxic lipid peroxidation product, 4-hydroxynonenal. We conclude that maternal E consumption induces oxidative stress in fetal tissues and that this is responsible for some toxic responses to E. Additionally, the low antioxidant defenses in fetal tissues and accumulation of toxic aldehyde products of lipid peroxidation predispose the fetus to oxidative damage.

Prostaglandin E2 inhibition of fetal breathing movements is not sustained during prolonged reduced uterine blood flow in sheep

Fetal breathing movements (FBM) are inhibited by both exogenous prostaglandin E2 (PGE2) and ethanol in sheep. Maternal ethanol exposure in late-gestation sheep also increases fetal [PGE2]. However, during prolonged reduced uterine blood flow (RUBF) when [PGE2] in fetal plasma is already elevated, FBM are not inhibited by ethanol. These experiments were designed, therefore, to test the hypothesis that the FBM response to PGE2 is also diminished during RUBF. PGE2 (594 ± 19 ng·min-1·kg-1 fetal body weight) was infused for 6 h into the jugular vein of RUBF (PO2 = 14 ± 1 mmHg (1 mmHg = 133.3 Pa); n = 7) and control (PO2 = 22 ± 1 mmHg (p &lt; 0.01); n = 7) ovine fetuses, and the effect on FBM, electrocortical (ECoG), and electroocular activities was determined. The infusion of PGE2 increased plasma [PGE2] from 881 ± 162 to 1189 ± 114 pg·mL-1 in RUBF fetuses and from 334 ± 72 to 616 ± 118 pg·mL-1 (p &lt; 0.05) in control fetuses. FBM were initially inhibited by PGE2 from 22.5 ± 9.4 and 17.9 ± 6.5% of the time to 6.9 ± 2.4 and 0.5 ± 0.4% (p &lt; 0.01) in RUBF and control fetuses, respectively. FBM remained inhibited in control fetuses throughout the infusion but returned to baseline incidence in RUBF fetuses in the last 2 h of the infusion. These results are consistent with the hypothesis that one component of the adaptative mechanisms of the fetus to prolonged RUBF is an altered response of FBM to exogenous PGE2. We speculate that the lack of a sustained inhibition in FBM during RUBF with infusion of PGE2 may be a result of an alteration in brainstem receptor function or number or local PGE2 removal.Key words: fetal breathing movements, prostaglandin E2, hypoxia, reduced uterine blood flow, ethanol, fetal behaviour.

Defective Intracellular Processing of Lactase‐Phlorizin Hydrolase Protein in Rats Prenatally Exposed to Ethanol

We have previously shown that fetal exposure to ethanol in rats produces both structural and biochemical abnormalities in absorptive enterocytes. Among the indicators of injury are derangements in the expression of lactase-phlorizin hydrolase (LPH), which is an essential enzyme for the assimilation of milk. In an animal model of fetal alcohol syndrome, unsuckled newborn rats prenatally exposed to maternal ethanol revealed a 10- to 15-fold increase in the number of LPH mRNA molecules per absorptive enterocyte, compared with controls (Estrada et al., Alcohol. Clin. Exp. Res. 20:1662-1668, 1996). However, lactase activity per cell was similar in both groups. The aim of this study was to characterize the effect of prenatal exposure to ethanol on the processing of LPH mRNA and protein. RNase protection assays using 3'- and 5'-directed antisense RNA probes revealed that the LPH mRNA from ethanol-exposed pups is full length. However, metabolic labeling, followed by immunoprecipitation using an anti-LPH monoclonal antibody, demonstrated a significant alteration in LPH protein processing. Intestinal explants from 21-day ethanol-exposed fetuses that were chased 30 min after a [35S]methionine pulse showed greater amounts of newly synthesized LPH precursors (205 and 220 kDa) and low molecular weight degradation products than controls. However, despite the increases in LPH precursor, the amount of 130 kDa mature LPH was similar in ethanol-exposed and control explants. These data suggest an increase in intracellular degradation of LPH precursor in rats prenatally exposed to ethanol, which occurs before its insertion into the microvillus membrane. Biosynthesis of LPH appears to be upregulated at the transcriptional level, which overcomes the degradation of LPH precursor during processing.

The computerized perinatal database: are the data reliable?

The purpose of this study is to examine the correctness of the clinical data from the computerized perinatal database (PC-Log) at a Mayo Health System hospital. This computerized database is used for electronic transmission of birth certificates in Wisconsin. The paper medical record is chosen for the comparison. Random selection of 99 charts from a total of 893 births at a tertiary perinatal center during 1995. Of 310 fields in the database, 32 variables were compared to a hand abstraction of the paper medical record. PC-Log had 100% positive-predictive value (PPV) for eclampsia, prolonged rupture of membranes, pre-existing diabetes, cesarean section, and transports. The sensitivity, specificity, and PPV for other variables (abortion, congenital anomalies, gestational diabetes, maternal hypertension, and maternal employment) showed moderate to high agreement, but was poor for maternal ethanol use during pregnancy. Compared to hand abstraction, PC-Log had no recorded cases of substance abuse, antenatal steroids, hyaline membrane disease, circumcision, maternal and infant length of stay. Means for birth weight 5 minute Apgar scores did not differ, and the correlations were r = 0.982 and r = 0.960. The PC-Log showed good agreement for many but not all the variables of clinical interest.

Neuroanatomical and neurophysiological mechanisms involved in central nervous system dysfunctions induced by prenatal alcohol exposure.

One of the most severe consequences of maternal ethanol consumption is the damage to the developing central nervous system, which is manifested by long-term cognitive and behavioral deficits in the offspring. Prenatal exposure to ethanol affects many crucial neurochemical and cellular components of the developing brain. Ethanol interferes with all of the stages of brain development, and the severity of the damage depends on the amount of ethanol intake and level of exposure. Experimental observations also indicate that the toxic effects of ethanol are not uniform: some brain regions are more affected than others and, even within a given region, some cell populations are more vulnerable than others. The neocortex, the hippocampus, and the cerebellum are the regions in which the neurotoxic effects of ethanol have been associated with the behavioral deficits. At the cellular level, ethanol disrupts basic developmental processes, including interference with division and proliferation, cell growth, and differentiation and the migration of maturing cells. Alterations in astroglia development and in neuronal-glial interactions may also influence the development of the nervous system. An impairment of several neurotransmitter systems and/or their receptors, as well as changes in the endocrine environment during brain development, are also important factors involved in the behavioral dysfunctions observed after prenatal ethanol exposure. Finally, some molecular mechanisms of ethanol-induced behavioral dysfunctions will be discussed.

A comparative study of ethanol, hypoglycemia, hypoxia and neurotrophic factor interactions with fetal rat hippocampal neurons: a multi-factor in vitro model for developmental ethanol effects

Fetal alcohol syndrome (FAS) is characterized by numerous central nervous system anomalies, with the hippocampus being particularly vulnerable to developmental ethanol exposure. In addition to direct ethanol neurotoxicity, other conditions resulting from maternal ethanol consumption, such as hypoglycemia and hypoxia, may also contribute to FAS. The present study used a tissue culture system to model multiple conditions which may relate to in vivo FAS, and assessed their relative neurotoxicity with MTT assays. Gestational day 18 rat hippocampal cultures were exposed to varying ethanol concentrations, glucose withdrawal-induced hypoglycemic (gwHG, 16 h) or acute hypoxic (aHP, 2 h) conditions alone, as well as to co-treatments with ethanol and gwHG or aHP. Brain-derived neurotrophic factor (BDNF) and nerve growth factor (NGF) have previously been shown to ameliorate ethanol-, hypoglycemia- and hypoxia-induced neurotoxicity. Therefore, their neuroprotective potential, along with ciliary neurotrophic factor (CNTF), was examined. Neuronal viability was reduced dose-dependently by ethanol, alone or with hypoglycemia or hypoxia. Ethanol+gwHG or aHP was not uniformly additive. NGF treatment provided the most extensive neuroprotection, being effective against ethanol (200 and 400 mg/dl), gwHG, and aHP, alone and combined. BDNF afforded similar protection, but not against ethanol+gwHG. CNTF protected only against aHP. CNTF+BDNF, previously shown to act synergistically, protected against ethanol+aHP up to 800 mg/dl ethanol, but not, paradoxically, against ethanol alone, gwHG, or ethanol+gwHG, all conditions BDNF alone protected against. This study demonstrated that several neurotrophic factors are capable of mitigating neurotoxicity associated with ethanol, hypoglycemia and hypoxia.

Zinc intestinal absorption in newborn rats at 21 day postpartum: Effects of maternal ethanol consumption

This study was designed to examine the effects of prenatal and postnatal exposure of ethanol in the in vivo absorption of zinc in the small intestine in newborn rats at the 21 st day after birth. The rats were accustomed to increasing amounts of ethanol (5 to 20 %, vol/vol) in tap water for 1 month. During pregnancy and suckling period, ethanol-fed dams were assigned again to ethanol 20 % in drinking water. Two sets of experiments were performed. In the first set, jejunal zinc absorption in control group and litters nursed by dams receiving ethanol showed a gradual increase along with the increase of perfusion time at all the assayed concentrations. In general, in litters of ethanol-fed dams, jejunal zinc absorption expressed as nmol/intestinal surface was higher than in control animais. In the second set of experiments, distal ileum zinc absorption in offspring of ethanol-fed dams showed a significantly decrease at all concentrations tested. The results showed that intestinal parameters measured in jejunum and distal ileum of litters exposed to ethanol were always significantly less than in control newborn. These results indicate that exposure of rats to ethanol during the pregnancy and suckling period, may affect postnatal development of intestinal functions and decrease the distal ileum zinc absorption in pups at the end of the lactation period.